During conventional subsea drilling operations, hydrocarbon gases are sometimes released from the formation and into the atmosphere. One such example is methane gas, which exists in subsea formations as methane hydrate, a crystallized methane deposit primarily located in vast amounts at shallow depths beneath the ocean floor. In addition, this crystallized methane may cap even larger deposits of gaseous methane.
Recovery of methane hydrates is difficult because it will not flow in the subsurface environment, as it only exists in a solid form. In addition, the methane hydrates may disappear through a phenomenon referred to as “sublimation.” Sublimation is the process by which a compound, through alteration of its temperature or pressure, transforms directly from a solid to gas phase, without passing through an intermediate liquid phase. As such, when the delicate pressure or temperature balance of the downhole environment is disturbed, the methane hydrates sublimate, thus escaping up through the formations and seawater, then out into the atmosphere where they only contribute to the controversial greenhouse gas problem. Thus, the traditional way of recovering hydrocarbon deposits through drilling wellbores into the hydrocarbon bearing formations, and letting the hydrocarbons flow into the wellbore and up to surface, is not feasible.
In view of the foregoing, there is a need in the art for cost-effective method by which to recover hydrocarbon gases from the seabed, thereby preventing the release of harmful gases into the atmosphere while also harnessing valuable hydrocarbon for further use.